Given its favourable position as a road junction, controlling a crossing over the Sieve river, Borgo San Lorenzo acquired a certain importance that allowed it to prevail over the entire surrounding area and to become the market town.

This power gradually weakened in relation to the economic growth of Borgo, which in the early 13th century affected the whole of Mugello; this is also demonstrated by the use of its own measures in transactions, such as the staio and the mina burgensi.

Subsequently, there were further attempts to revolt against the bishop's authority, which in 1239 forced the then Podestà, Ubaldino della Pila, to issue an order prohibiting the building of houses and towers over 15 fathoms high.

The spirit of rebellion was led by the Guelph nobles who, in 1251, had to suffer the assault of the Ghibellines who had escaped from Florence, allied with the Lords of Romagna.

The town was the main centre of a league that brought together all the inhabitants of the area; it was the seat of political power, represented by a Podestà sent every six months from Florence; the men who held all public offices were also Florentine.

Under the Hapsburg-Lorraine of Tuscany, Borgo San Lorenzo became the main centre of the entire Mugello, thanks to the centrality of its position in the area and the increase in building and agriculture brought about by Grand Ducal policy.